I had a problem with a conservatory installer a few years ago and he was dragging his heels over putting right some problems that he knew about from the start of the installation. I sent him only one letter but it had at the bottom -
cc. ****** ******, Consumer Affairs Editor, Sunday Life
(our local Sunday paper in NI)
cc. Glass & Glazing Federation
cc. Conservatory Association
And to top it off, I threatened to inform his UK mainland conservatory supplier by post, phone and email and tell everyone who would listen not to buy their products through him.
After that letter, the problems were fixed within a week.
As Corporal Jones would say, "they don't like it up'em!"